1. Field of the Invention
The present invention relates to a structure of a pixel and a fabricating method thereof, and more particularly to a structure of a pixel with an electrical field shielding layer between a data line and a pixel electrode for avoiding the interference between the data line and the pixel electrode, and a fabricating method thereof.
2. Description of the Related Art
Thin Film Transistor Liquid Crystal Display (TFT LCD) comprises a thin film transistor array substrate, a color filter array substrate and a liquid crystal layer. The thin film transistor array substrate is composed of a plurality of pixels arranged in arrays. Each pixel comprises a thin film transistor, a pixel electrode and pixel storage capacitor. The thin film transistor comprises a gate terminal, a channel, a drain terminal and a source terminal, which are used to control the device. When the pixel electrode is in on-state, a signal is written into the pixel; when in off-state, a pixel storage capacitor can maintain the potential required for driving the device. Therefore, the capacitance of the pixel storage capacitor is closely related with the performance of the liquid crystal display.
In the prior art pixel storage capacitor of the pixel comprises a first metal layer, a second metal layer and a dielectric layer therebetween. Whether it is a Cst-on-gate structure or a Cst-on-common structure, the gate terminal or the common line, i.e. the first metal layer, serves as an electrode; the second metal layer and the pixel electrode electrically coupled thereto serve as another electrode. However, because the prior pixel storage capacitor uses the opaque metal layer as the capacitor electrode, it substantially reduces the aperture ratio of the pixel storage capacitor, reducing brightness of the displays.
For solving the issue of reduction of the aperture ratio of the pixel, another structure of a pixel is disclosed by a prior art. FIG. 1 is a schematic cross-sectional view showing the structure of the pixel. Referring to FIG. 1, a pixel 100 is disposed on a substrate 110. The pixel 100 comprises a scan line (not shown), a data line 130, an active element 140 and a pixel storage capacitor 150. The scan line and the data line 130 are disposed on the substrate 110. The active element 140 is disposed on the substrate 110 and near to the intersection of the scan line and the data line 130. The pixel storage capacitor 150 comprises a pixel electrode 152 and a transparent capacitor electrode 154. The pixel electrode 152 is electrically coupled to the active element 140.
Because the pixel electrode 152 and the transparent capacitor electrode 154 of the pixel storage capacitor 150 are made from transparent materials, the pixel storage capacitor 150 does not result in the reduction of aperture ratio in pixel 100. However, the capacitance of the structure is reduced because of the shrinkage thereof. If the distance between the pixel electrode 152 and the transparent electrode 154 is reduced, the capacitance of the pixel storage capacitor 150 is enhanced, but the interference between the pixel electrode 152 and the data line 130 arises, resulting in the worse performance of the liquid crystal displays.